Numerous devices are known for taking hold of receptacles installed on packaging machines. In most cases, it is possible to use gripping tongs whose jaws are urged resiliently towards a closed position, the receptacles being inserted into or extracted from the tongs by means of guide ramps that are suitably disposed adjacent to the zone in which the receptacles are inserted or extracted. Such tongs are commonly used to hold a receptacle vertically under a filling spout or a heat-sealing head for affixing a heat-sealed closure film.
However, for a station at which caps are screwed on, it is necessary not only to hold the receptacle vertically under the cap-screwing head but also to hold it so as to prevent it from turning while tightening torque is being applied to the cap. In existing devices, an element provided with spikes is generally provided, the spikes being disposed to penetrate into the material forming the receptacle when it is inserted into the cap-screwing station. Those devices suffer from the drawback of locally damaging the receptacles. In addition, inserting and extracting the receptacles gradually causes the spikes to wear so that, after a certain number of operating cycles, it is necessary to change the spike-carrying locking member so that it continues to perform its locking function for preventing the receptacles from turning.